As bizarre as this is going to sound....After eating lunch, we noticed that the patio umbrella on our deck was smoldering!

Apparently during the storms of the past couple of weeks one of our window screens blew off and the low-angle winter sun was reflecting off of the low E window coating and onto the umbrella causing it to spontaneously combust.

That's our best guess.....If anyone has another explanation please post.

We hurriedly took it down, put it in the shade and snapped the pics.

Scary stuff, as we live in an extreme fire hazard area and our deck and house are both slathered with linseed oil.

Did you consider the possibility of spontaneous combustion caused by fresh linseed oil fumes trapped under (and in) a hot umbrella canopy? Did you apply linseed oil to the wooden umbrella frame?

Just a wild idea...

Looney

The linseed oil isn't that fresh. We re-stained the deck several months ago and the house hasn't been stained in a few years.

The umbrella was down since the storms, my girlfriend put it up yesterday morning and noticed the smoldering right after lunch. We have pretty much confirmed that it was the sun reflecting off of the window, see pics. The first pic is seconds before we took it down, note the burned spots and the concentrated sun spot. I took the second pic this morning, and you can see the additional burn mark from the above sun spot.

I'm still puzzled why there are burn "spots" and not a track based on the suns position. Our best guess on that is that the sun was shining through tree branches behind the house.

As bizarre as this is going to sound....After eating lunch, we noticed that the patio umbrella on our deck was smoldering!

Apparently during the storms of the past couple of weeks one of our window screens blew off and the low-angle winter sun was reflecting off of the low E window coating and onto the umbrella causing it to spontaneously combust.

That's our best guess.....If anyone has another explanation please post.

We hurriedly took it down, put it in the shade and snapped the pics.

Scary stuff, as we live in an extreme fire hazard area and our deck and house are both slathered with linseed oil.

I'm going to wager it was nothing more than strong South California sun reflected and effectively focused on that umbrella by a very reflective window on particularly sunny day.

Even here in MA such things are possible on a hot summer day. I've cooked using a solar oven in this Northern environment so I imagine in S. Cal this would not be hard.

The Trolley Museum in Kennebunk, ME. some years ago lost a trolley car to a fire that started due to spare clerestory windows stored in it that concentrated the sun's rays on a hot summer day. That antique trolley car burned to the ground..

__________________"To argue with a person who has renounced the use of reason is like administering medicine to the dead." - Thomas Paine

I'm going to wager it was nothing more than strong South California sun reflected and effectively focused on that umbrella by a very reflective window on particularly sunny day.

Our deck is south facing and it gets hotter than a pistol in the summer. It's hot again today and already too hot to walk on the deck in bare feet.

A few years ago when we were into home brewing, I left a 5 gallon glass carboy out on the deck full of water for a few hours. Same thing, burned a crescent shaped mark into one of the deck boards. The glass/water combo focused the light.

Our deck is south facing and it gets hotter than a pistol in the summer. It's hot again today and already too hot to walk on the deck in bare feet.

A few years ago when we were into home brewing, I left a 5 gallon glass carboy out on the deck full of water for a few hours. Same thing, burned a crescent shaped mark into one of the deck boards. The glass/water combo focused the light.

BTW Kevin: I'm originally from your neck of the woods....Dedham, MA.

It's hot here 2 , stepped out on to the deck and it must have been 62 degress